DENIERS SAY:

After they gave up on the notion that global warming is real, they started calling it 'climate change' instead.

SCIENCE SAYS:

You can call it global warming or climate change, but it's the biggest crisis humanity has ever faced.

“Global warming” and “climate change,” while closely related and sometimes used interchangeably, technically refer to two different things. “Global warming” applies to the long-term trend of rising average global temperature. “Climate change” is a broader term that reflects the fact that carbon pollution does more than warm our planet. It is also changing rain and snow patterns and increasing the risk of intense storms and droughts. The term “climate change” has actually been around longer than “global warming." Gilbert Plass published the study “The Carbon Dioxide Theory of Climatic Change” in 1956! And although “global warming” seems to have first appeared in a 1957 newspaper editorial, the term is widely attributed to Wallace Broecker’s 1975 paper “Climatic Change: Are We on the Brink of a Pronounced Global Warming?” Don’t fall prey to the idea that the increased popular usage of “climate change” means global warming is no longer happening. Both climate change and global warming are still a reality.

Additional info from NASA

Whether referred to as "global warming" or "climate change," the consequences of the wide scale changes currently being observed in Earth's climate system could be considerable.

The Internet is full of references to global warming. But we don't use global warming much at NASA. We use the less appealing "climate change." Why?

To a scientist, global warming describes the average global surface temperature increase from human emissions of greenhouse gases. Its first use was in a 1975 Science article by geochemist Wallace Broecker of Columbia University's Lamont-Doherty Geological Observatory: "Climatic Change: Are We on the Brink of a Pronounced Global Warming?"

Broecker's term was a break with tradition. Earlier studies of human impact on climate had called it "inadvertent climate modification." This was because while many scientists accepted that human activities could cause climate change, they did not know what the direction of change might be. Industrial emissions of tiny airborne particles called aerosols might cause cooling, while greenhouse gas emissions would cause warming. Which effect would dominate?

For most of the 1970s, nobody knew. So "inadvertent climate modification," while clunky and dull, was an accurate reflection of the state of knowledge.

The first decisive National Academy of Science study of carbon dioxide's impact on climate, published in 1979, abandoned "inadvertent climate modification." Often called the Charney Report for its chairman, Jule Charney of the Massachusetts Institute of Technology in Cambridge, it declared: "If carbon dioxide continues to increase, [we find] no reason to doubt that climate changes will result and no reason to believe that these changes will be negligible."

In place of inadvertent climate modification, Charney adopted Broecker's usage. When referring to surface temperature change, Charney used "global warming." When discussing the many other changes that would be induced by increasing carbon dioxide, Charney used "climate change."

During the late 1980s one more term entered the lexicon, “global change.” This term encompassed many other kinds of change in addition to climate change. Climate research was embedded as a theme area within the U.S. Global Change Research Program when it was approved in 1989.

Global warming became the dominant popular term in June 1988, when NASA scientist James E. Hansen had testified to Congress about climate, specifically referring to global warming. He said: "Global warming has reached a level such that we can ascribe with a high degree of confidence a cause and effect relationship between the greenhouse effect and the observed warming." Hansen's testimony was very widely reported in popular and business media, and after that popular use of the term global warming exploded. Global change never gained traction in either the scientific literature or the popular media.

But temperature change itself isn't the most severe effect of changing climate. Changes to precipitation patterns and sea level are likely to have much greater human impact than the higher temperatures alone. For this reason, scientific research on climate change encompasses far more than surface temperature change. So "global climate change" is the more scientifically accurate term. Like the Intergovernmental Panel on Climate Change, we've chosen to emphasize global climate change at NASA, and not global warming.